/Engine/Source/Editor/UnrealEd/Classes/ThumbnailRendering/SkeletalMeshThumbnailRenderer.h
class USkeletalMeshThumbnailRenderer : public [UDefaultSizedThumbnailRenderer](API\Editor\UnrealEd\ThumbnailRendering\UDefaultSizedThumbnailRenderer)
TObjectInstance...
ThumbnailSceneCache